Mexico is an exotic land, and no place drives this home more forcefully than a mountain forest where you stand surrounded by the fluttering wings of millions of monarch butterflies it’s like being in a fairy tale. The setting is the rugged highlands of Michoacán, from mid to late November through March. A visit to the winter nesting grounds of the monarch butterfly, high in the mountains of northeast Michoacán, is a stirring experience. It might be the highlight of your trip. The season lasts from mid to late November to March. Tour operators in Morelia offer a day trip to see the butterflies. The tour takes 10 to 12 hours and involves hiking up a mountain at a high altitude. You should only do this trip if you’re in decent physical condition, or you can rent a horse instead. The best time to see the butterflies is on a sunny day, when they flutter through the air in a blizzard of orange and black. At the center of the group, the branches of the tall fir trees bow under their burden of butterflies, whose wings undulate softly as the wind blows through the forest; it’s quite a spectacle. A few butterfly sanctuaries are open to the public. (The monarchs congregate at nine sites, but five are closed to visitors.) The sites with the best access are El Rosario (daily 10am–5 or 6pm) and the newer Chincua (same hours as El Rosario). It is less of a drive, but usually more of a walk to the nucleus of the butterfly group but not always. Throughout the season, the groups shift, moving up and down the mountains and making for a longer or shorter climb. A good guide will be aware of which is the shorter walk. If you’re driving, take the autopista to Mexico City, exit at Maravatío, and go right. Keep right after going through Maravatío and take the narrow two-lane road toward Angangueo. When you get to a T-junction, go right, toward San Felipe. Enter the town of Ocampo and look for a small sign pointing left to get to Rosario, where you will find a parking lot near the trail head. If you want to make this a leisurely trip, spend the night in the nearby town of Angangueo. Travel agencies from San Miguel de Allende also book monarch tours, which take 1 or 2 days. Santuario El Rosario is one of two sanctuaries open to the public in the Monarch Butterfly Biosphere Reserve in the mountains west of Mexico City. The 160-sq-km (60-sq-mile) preserve is the winter home of an estimated 100 million monarch butterflies, which migrate here each year from northern US and Canada. The mystery of where monarchs overwinter was solved by Canadian zoologist Fred Urquhart, who found the isolated roosts in the 1970s. The best time to visit is late February is when rising temperatures encourage the insects to search for flowers or begin their journey back north. The hiking route is well marked. The nearby Sierra Chincua Monarch Butterfly Sanctuary sees fewer visitors than El Rosario, but is easier to reach and offers horses for its more rustic trails. Guides will accompany visitors on request. The annual migration of the monarch butterfly (Danaus plexippus linneo) begins in the northern parts of North America in early autumn. It is then that a special generation hatches, with a life cycle of up to nine months, four times that of spring and summer butterflies. These autumn-born individuals fly south in groups of several hundred to escape the winter. They cover up to 300 km (190 miles) a day and within a month reach the oyamel fir forests of central Mexico where they spend the winter. In spring they mate and head north again. En route, the females lay about 500 eggs each. Their offspring take up the baton and continue north to arrive in early June. None of the original migrants will survive to return to Mexico the following year.

Each winter more than 150 million monarch butterflies migrate from the northeastern US and Canada to the Oyamel fir forests in the lush mountains of Michoacán in order to reproduce. It’s an amazing sight any time, but especially in January and February when numbers peak: whole trees are smothered in monarchs, branches sagging under the weight. In the cool of the morning, they dry their wings, turning the entire landscape a rich, velvety orange, while later in the day they take to the air, millions of fluttering butterflies making more noise than you’d ever think possible. As the afternoon humidity forces them to the ground, they form a thick carpet of blazing colour. The best place to see them is in the Santuario de la Mariposa Monarca, just outside the village of El Rosario, about 120km east of Morelia. It is best to go early in the morning (and preferably on weekdays, to avoid the crowds), when the butterflies are just waking up and before they fly off into the surrounding woodlands. Guides, whose services are included in the entry fee, show you around the sanctuary and give a short explanation of the butterflies’ lifecycle and breeding habits. For a couple of weeks on either side of the main season, those same guides run the place unofficially, still charging the entry price and offering their services for a tip. There are fewer butterflies but it is still worth the journey anytime from early November to early April. The walk to the best of the monarch-laden trees is about 2km, mostly uphill at an altitude of almost 3000 metres: take it easy if you’re not acclimatized or rent a horse. Visiting the monarchs is possible on day trips from Morelia and Mexico City, but it is more satisfying to stay locally (probably in Angangueo) and visit at a more leisurely pace. During the season there are direct buses to El Rosario from Mexico City (Autobuses Zincantepec from Terminal Poniente), but otherwise getting there by public transport generally involves changing buses in Zitácuaro. From Zitácuaro, buses run to Ocampo (every 15min; 30min) and continue to Angangueo (a further 20min). From Ocampo there is a minibus along a 10km cobbled road to El Rosario (every 15min; 30min). Those with a car can drive direct to El Rosario from Ocampo. If you are staying in Angangueo you could conceivably walk back downhill in a couple of hours. There are also basic daytime restaurants that line the approach to the sanctuary. All other accommodation and dining options are in Ocampo and Angangueo.

The sheer size of the congregation of monarch butterflies in the hills of Michoacán is astonishing, but not as impressive as their 4500-kilometre migration. In the fall, when the weather starts to turn cold in the Great Lakes region of the US and Canada, the butterflies head south, taking just four to five weeks to make it to Michoacán. Here, in an area of less than 150 square kilometres, they find the unique microclimate a perfect place to spend the winter. The cool temperatures allow them to conserve energy, the trees provide shelter from wind and precipitation and the fog-laden air prevents them from drying out. Monarchs typically have a life cycle of around two to five weeks, but when they fly south they go into a phase known as “reproductive diapause”. The same butterflies remain in Michoacán all winter, then breed in spring in time for their caterpillars to dine on the newly emergent milkweed plants – their only food source – before returning to the US and Canada. Around ten percent of all migrating monarchs get eaten by black-headed grosbeaks and black-backed orioles, but that offers no danger to species survival. The real threat is loss of this crucial mountain habitat. This was recognized as far back as 1986, when several key overwintering sites were protected from logging, but the local peasant families need the wood and they were never fully compensated for the loss of this resource. The Mexican government more than tripled the size of the reserves in 2000, but logging continued to a large enough extent that in early 2007 declared a “zero tolerance” policy against it, and increased policing.

Reserva Mariposa Monarca: In the easternmost corner of Michoacán, straddling the border of Mexico state, lies the incredible 563-sq-km Monarch Butterfly Reserve, the site of the butterfly Burning Man. Every autumn, from late October to early November, millions of monarch butterflies flock to these forested Mexican highlands for their winter hibernation, having flown all the way from the Great Lakes region of the US and Canada, some 4500km away. Sometime around the autumnal equinox, they begin their journey alone - flying 12km per hour within 150m of the ground. As they close in on their destination they gather in gentle swarms, crossing highways and fluttering up steep mountain-sides where they cling together in clusters that weigh down thick branches of the oyenal (fir) trees. When the sun rises and warms the forest, they take to the sky in gold and orange flurries, descending to the humid forest floor for the hottest part of the day. By midafternoon they often carpet the ground brilliantly. The best time to see them is on a warm, sunny afternoon in February (they don't fly as much in cool weather), when the butterflies have already begun their slow descent down the mountain. In the warm spring temperatures of March the butterflies reach their sexual maturity and the real fun begins. Males fly carrying the females beneath them as they mate - abdomen to abdomen. Each female attracts multiple partners to ensure reproduction and exhausted males don't fall asleep immediately after sex - they die! When the vernal equinox strikes, pregnant females fly north to the southeastern US, where they lay their eggs in milkweed and die fulfilled. Their eggs hatch into caterpillars that feed on the milkweed, then make cocoons and emerge in late May as new butterflies. These young monarchs flutter back to the Great Lakes, where they breed, so that by mid-August yet another generation is ready to start the long trip south. It takes from three to five generations of butterflies (living one to eight months each) to complete the entire round-trip journey from Canada to Mexico and back This is one of the most complex animal migrations on earth and scientists still have no idea how or why they do it. But they must tune into some kind of mariposa collective consciousness hardwired into their dynamic DNA. Monarch butterflies are not in danger of extinction - there are thriving colonies in other Nits of the world. However, the migratory behavior of this particular population is threatened. Milkweed, the plant upon which the monarchs depend, is considered invasive in most of the southeast US and is being sprayed with insecticides.

Habitat destruction is also a problem; the area is ecologically significant enough to have been decreed a Reserva de la Biosfera (giving it protected status), but illegal logging still occurs in up to 60% of reserve lands. Local farmers, most strapped for cash, cut down the precious wood, plant corn and allow their livestock into butterfly territory. Some organizations are trying to change these patterns, offering local communities’ incentives to not only protect their remaining forests, but also to restore habitat via tree planting projects. Visiting the Reserve The reserve is divided into five separate areas, four of which are open to visitors from mid-November through March, but exact opening dates depend on weather, temperatures and the butterflies' arrival. El Rosario and Sierra Chincua are the most popular reserve areas. Both are accessible from Angangueo, the closest town to Sierra Chincua (just 8km away) and the best base for this end of reserve. El Rosario is close to the pueblo of the same name and can be reached from Angangueo via Ocampo. Cerro Pelon is the newest reserve area and has the healthiest habitat. It's best reached from Ziticuara At the beginning or end of the season ask for information on butterfly activity at the Morelia or Mexico City tourist offices before heading out here. Some people do day trips or tours from Morelia or Mexico City to see the butterflies, but this means more than eight hours of travel in one day. Ifs better to take your time and enjoy this unique and beautiful region. The reserve areas are spread out, so you'll probably or be able to visit one. But the butterflies all look and behave the same in each spot. El Rosario, which is also the name of a nearby village, is the most popular area and the easiest to reach via public transportation from Angangueo. But during the height of butterfly voyeurism (February and March) they get as many as 8,000 visitors a day. It is also the most commercial souvenir stalls abound on the hillside and the habitat has been severely impacted by illegal logging. El Rosario village and the entrance to the El Rosario reserve area are located about 12km up a good gravel road from the small village of Ocampo. Getting to the butterflies requires a steep hike (or horse ride) of 2km to 4km from the reserve's parking lot, depending on the time of year. There are a couple of hotels in Ocampo, but you should stay in the cute village of Angangueo (just 45 minutes from Ocampo). Sierra Chincua is 8km beyond Angangueo, way up in the mountains. This area has also been damaged by logging, but not as badly as El Rosario. It’s a less strenuous hike, so this sanctuary is for those who want an easier walk. Cerro Penton, which is actually located in Mexico State, is the newest reserve area and by far the best choice. The mountains rise high (over 3000m) here, the forest is in great shape and there is barely a trickle of tourism (on its busiest day it may get 80 visitors, when we visited we were all alone on the mountain). Logging has been eliminated and local guides have replanted trees for years to restore habitat. Expect to see huge, cathedral fir trees, moss covered trunks, wildflowers and incredible canyon views. Camping in a natural meadow just below Cerro Pelon peak, only an hour's hike from where the butterflies gather in the early season, is a terrific option. Guides will arrange burros to haul the heavy stuff up the mountain. This reserve area is about a 40-minute drive southeast of Zitacuaro, Michoacan's third-largest city, where you can buy necessary food, water and supplies. You should bring your own camping gear. There are a couple of access points Macheros and El Capulin. Both are within 1.5km of each other and can be reached by public transportation from outside Ziticuaro s bus terminal. A taxi straight from Zitacuaro to either of the reserve areas. The steep hike from the sanctuary entrances to the butterflies can take from 90 minutes to over two hours depending upon your condition. Daily admission for each reserve area is very cheap and all areas rotate compulsory local guides. Expect to pay for horse, if you don't want to hike, plus the guide. Note that the length of your hike/horseback ride will be shorter later in the season the butterflies work their way down as the weather warms up.

Angangueo, this sweet, drowsy old mining town is the most popular base for butterfly-watchers, because it's dose to both the Sierra Chincua and the El Rosario sanctuaries. The town is layered into the hills, knitted with pine forest, grazing land and cornfields. Most services can be found along a single main drag with two names (Nacional and Morelos). Stop at the tourist office just downhill from the plaza. Cheap sleeps include decent and basic rooms encircling a gorgeous flower garden. You may have to shout for service. Frequent buses from Morelia go first to Zitacuaro (three hours) where you'll hop another bus to Angangueo (1 hour). From Mexico City's Terminal Poniente you can take Autobuses MTZ (four hours, four daily) direct to Angangueo; but the majority of buses go through Zitacuaro. To reach the El Rosario sanctuary from Angangueo, first take a combi to Ocampo, then another to El Rosario, from the corner of Independencia and Ocampo. In season there are also camionetas (open-back trucks) that leave from the auditorio (auditorium) in Angangueo, or from outside hotels; around 10 people and take 45 bumpy minutes (via a back road) to reach the sanctuary.

Zitacuaro; Zitacuaro is Michoacan's third-largest city, but it feels like a provincial working-class town. Known primarily for its baked bread and trout farms, it is also the best base for visiting the butterflies at Cerro Pellon. Other attractions include the Iglesia de San Pancho in the village of San Pancho, just south of Zitacuaro. It's the restored 16th-century church that appeared in the great John Huston-Humphrey Bogart film, The Treasure of the Sierra Madre and was visited by Prince Charles in 2002. Come at sunset when light streams through the stained glass. About 16km north of Zitacuaro lie the peaceful Matlazinca ruins, Piramides Los Alzati (10am-5pm). Veterans of other archaeological sites won't be too impressed by the pyramids, but the views are great and it’s a nice picnic spot. The main drag, Av Revolucion, is where you'll find most hotels and restaurants. People in the plaza is passionate about the butterflies and offers detailed maps, driving directions and shows background videos to interested guests. Can also arrange transportation to and from the sanctuaries. The grounds are huge with stands of pine and fruit trees and great canyon views. High is where it happens Monarch butterflies like basking at altitude, so getting to them requires hiking (or horseback riding) up to 3000m. Hike slowly, remember to take plenty of breaks (and water) and be aware of the symptoms of altitude sickness.